Re: [PATCH v3] iio: adc: Correct conditional logic for store mode

[Jonathan Cameron <jic23@kernel.org>]

On Tue, 15 Apr 2025 09:54:00 -0400
Gabriel Shahrouzi <gshahrouzi@gmail.com> wrote:

> On Tue, Apr 15, 2025 at 5:13 AM Nuno Sá <noname.nuno@gmail.com> wrote:
> >
> > On Mon, 2025-04-14 at 11:40 -0400, Gabriel Shahrouzi wrote:  
> > > The mode setting logic in ad7816_store_mode was reversed due to
> > > incorrect handling of the strcmp return value. strcmp returns 0 on
> > > match, so the `if (strcmp(buf, "full"))` block executed when the
> > > input was not "full".
> > >
> > > This resulted in "full" setting the mode to AD7816_PD (power-down) and
> > > other inputs setting it to AD7816_FULL.
> > >
> > > Fix this by checking it against 0 to correctly check for "full" and
> > > "power-down", mapping them to AD7816_FULL and AD7816_PD respectively.
> > >
> > > Fixes: 7924425db04a ("staging: iio: adc: new driver for AD7816 devices")
> > > Cc: stable@vger.kernel.org
> > > Signed-off-by: Gabriel Shahrouzi <gshahrouzi@gmail.com>
> > > ---  
> >
> > LGTM, do you happen to have this device? It would more interesting to move this
> > driver out of staging :)  
> Unfortunately, I do not have this device. However, I would still be
> interested in contributing if possible. I was looking over
> https://lore.kernel.org/all/20230716144024.30ded663@jic23-huawei/T/
> where the goal seemed to be to modernize it by replacing the sysfs
> interface with the iio channel. I also looked through the datasheet
> and it seemed to be missing some stuff like a channel that can be
> selected.
> >
> > Acked-by: Nuno Sá <nuno.sa@analog.com>
Applied to the fixes-togreg branch of iio.git but amended the patch title
to start wit
staging: iio: adc: ad7816: 

so people looking at a short log can see what it is touching.

Thanks,

Jonathan

> >  
> > > Changes since v3:
> > >       - Tag stable@vger.kernel.org instead of an email CC
> > >       - Use the correct version for patch
> > > Changes since v2:
> > >       - Add fixes tag that references commit that introduced the bug.
> > >         - Replace sysfs_streq with strcmp.
> > > ---
> > >  drivers/staging/iio/adc/ad7816.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/staging/iio/adc/ad7816.c
> > > b/drivers/staging/iio/adc/ad7816.c
> > > index 6c14d7bcdd675..081b17f498638 100644
> > > --- a/drivers/staging/iio/adc/ad7816.c
> > > +++ b/drivers/staging/iio/adc/ad7816.c
> > > @@ -136,7 +136,7 @@ static ssize_t ad7816_store_mode(struct device *dev,
> > >       struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> > >       struct ad7816_chip_info *chip = iio_priv(indio_dev);
> > >
> > > -     if (strcmp(buf, "full")) {
> > > +     if (strcmp(buf, "full") == 0) {
> > >               gpiod_set_value(chip->rdwr_pin, 1);
> > >               chip->mode = AD7816_FULL;
> > >       } else {  
>